I'm considering using non-elastic cord instead of the usual elastic for suspension. It has one main advantage of being more durable and doesn't become loose over time.
I was thinking of a cord of the type that is used for shoe laces. (Nylon type cord is also an option, but I'm afraid it would make some more noise, like guitar strings .)

How does such a cord perform in terms of noise? In general I'd not just let the HDD hang on it, but I'd try to make the HDD stay in place by tightening the cord in all directions.

Sure seems like it wouldn't isolate the vibrations as well as something elastic, but give it a try. You've got nothing to lose but time and the cost of a shoelace. It' may be perfectly satisfactory to you, and it certainly solves the only negative issue I've ever seen with elastic suspension.

I think it might create additional resonsnace if I understand what you are proposing.

Take at look at these options:
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especially the noise magic

"Guitar string" is a good description as that's exactly what you'd have.

If drive security is an issue, I'd look at getting some small bungee cords from your local home improvement store. They can be cut, tied, and routed just about any way you want. More importantly, you can use some cable anchors (the kind you secure speaker or cable wires with) to lock your drive to the bungees.

This is similar to the stuff I used, it's perfect.

Manufacturers have made significant progress in HDD vibration and noise reduction in the last 5 years. If you have a recent HDD, then a simple silicone mount (like on Antec cases) should work just as well as suspension. If you have an older drive where this is not the case, then you might want to get a new one just to improve data reliability in addition to noise reduction. Prices have come way down also.

Just letting you know that I tried this in the lower cage of a P183 with an F3 and an F2 green.

First with a 3mm non elastic cord, like this:


And then with a 3mm bungee/shock cord:



The result: I cannot say with confidence that I notice a difference. This is probably also in part due to the silicon grommets between the cord and the metal casing, as you can see in the pictures. If I had to take a pick, I'd say that the elastic method is slightly better, but honestly it could as well be placebo.
They did both seem to be an improvement over the default mounting, tho. But not a big improvement, the default mounting is pretty good and should be fine for most people. But in my case, the HDDs are definitely the loudest components, since the fans are inaudible in idle.

I think to reach a definitive conclusion on acoustic properties of non-elastic cord suspension, we'd have to try it in more problematic cases, where any kind of suspension makes a big difference. The P183 is not such a case.

first time I tried suspending I used non-elastic cord, with the result that a lot of vibrations still got sent to the case via the cords:
viewtopic.php?p=546551#p546551